Transition metal catalysts, process for their preparation and their use

摘要

A catalyst with a transition metal immobilised on a support is prepared by reaction of a hydroxylated support with a transition metal alcoholate of formula M(OR)nQm. The symbols are defined in claim 1. The support is heated between 100 DEG and 300 DEG C with the transition metal alcoholate in excess in relation to the available surface hydroxyl groups, in an inert hydrocarbon and in the presence of water, to perform a reaction of condensation of the transition metal alcoholate or of its oligomer with the surface hydroxyl groups. The catalysts contain 3 to 60 % by weight of a transition metal present on and bonded to the support matrix by oxygen bridges so that the transition metal atoms are bonded to one another by oxygen bridges. The catalysts are particularly useful in the preparation of carboxylic acid esters.